joakim wrote:
Here is a question for you all:
How is the performance of the C/Y 50/1.4 Planar wide open and what is the main difference between it and the newer ZF/ZE versions?

Although the designs are similar, the newer version had to be tweaked to accommodate environmentally friendly glass types. As a result, is has more spherical aberration and a softer image at full aperture. Stopped down, both lenses are very good and difficult to tell apart.

Here is a comparison with two samples of the YC, and one ZE sample. Center crops at full aperture, a faraway and a nearby subject.